Section And Data Declaration; Default Sections - Fujitsu FR Series Application Note

4 Section and Data Declaration

The ANSI specification requires that global data are initialised. This has to be done by the
startup code. However, the compiler has to provide a mechanism to collect those data,
which have to be cleared (set to zero) and those data, which have to be pre-loaded with a
value. The FCC911S provides default sections, which contain dedicated groups of data. A
section is a unit that can be handled by the linker. It either contains initialised data or
reserved areas. All sections used in an application can be found in the linkage map after
linking project.

4.1 Default Sections

The compiler FCC911S has the following default sections
Section Type
Code section
Initialized section
Constant section
Data section
I/O section
Vector section
C++ Init section
Code section: The code section stores machine codes. This section corresponds to the
procedure section for the C language.
Initialized section: The initialized section stores the initial value attached variable area. For
the C language, this section corresponds to the area for external variables without the const
attribute, static external variables, and static internal variables. The ANSI specification
requires that global data are initialised. This is done during the startup code.
Constant section: The constant section stores the write-protected initial value attached
variable area. For the C language, this section corresponds to the area for const attribute
attached external variables, static external variables, and static internal variables.
Data section: The data section stores the area for variables without the initial value. For the
C language, this section corresponds to the area for external variables (including those
which are with the const attribute), static external variables, and static internal variables. The
ANSI specification requires that data section must be cleared. This is done during the startup
code.
I/O section: I/O section stores the area for the __io-qualified variables. For the C language,
this section corresponds to the area for __io-qualified external variables (including those
which are provided with the const attribute), static external variables, and static internal
variables. The default section name is IO.
Vector section: This section is where interrupt vector tables are stored. In C, a vector table is
generated only when its generation is specified in #pragma intvect. The default section name
is INTVECT.
C++ Init section: This section is where tables for indicating the entry of functions constituting
and destroying static objects are stored. It must be used at startup.
MCU-AN-300021-E-V10
Start91460.asm
Chapter 4 Section and Data Declaration
Section Name
CODE
INIT
CONST
DATA
IO
INTVECT
EXT_CTOR_DTOR
Type Bondary
Alignment
[Byte]
CODE 2
DATA 4
CONST 4
DATA 4
IO 4
CONST 4
CONST 4
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Write Initial Value
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